This document discusses bud dormancy in plants. It defines a bud as an undeveloped shoot that occurs in the axil of a leaf or stem tip. Buds can remain dormant for some time before developing. There are different types of buds based on location, status, morphology, and function. Terminal buds are at stem tips while axillary buds are in leaf axils. Resting buds form at the end of the growth season and will lie dormant until the next season starts. External factors like water, oxygen, and suitable temperatures can affect dormancy along with internal seed maturity and hormone levels.

1. BUD DORMANCY

2. CONTENTS
• Defination
• Introduction
• Types of bud
• Factors affecting dormancy

3. DEFINATION
• In botany ,a bud is an undeveloped or
Embryonic shoot and normally occurs in the
axil of a leaf or at the tip of stem.
• Once formed a bud may remain for some
time in condition, or it may form a shoot
immediately.
• Buds may be specialized to develop flowers
or short shoots ,or may have the potential for
general shoot development.

4. INTRODUCTION
• The buds of many woody plants, especially
in temperate or cold climates, are protected
by a covering of modified leaves called
scales.
• Which tightly enclose the more delicate
parts of the bud.
• Many bud scales are covered by a gummy
substance which serves as added protection.

6. • When the bud develops, the scales
enlarge somewhat but usually just drop
off, leaving on the surface of the growing
stem a series of horizontally elongated
scars.
• The minute underdeveloped leaves in
such buds are often excessively hairy.
• In many of the latter, buds are even
more reduced, often consisting of
undifferentited masses of cells in the
axils of leaves.

7. • A terminal bud occurs on the end of a
stem and lateral buds are found on the
side.
• Since buds are formed in the axil of
leaves, there distribution on the stem is
the same as that of leaves.
• in many plants buds appear in
unexpected places these are known as
adventitious buds.

8. TYPES OF BUDS
• Buds are often useful in the
identification of plants, especially for
woody plants in winter when leaves have
fallen.
• Buds may be classified and described
according to different criteria:-location
,status, morphology and function

9. FOR LOCATION:-
• TERMINAL:-When located at the tip of a
stem.
• AXILLARY:-When located in the axil of a
leaf.
• ADVENTITIOUS : When occurring
elsewhere for example on trunk or on
roots.

10. FOR STATUS:-
• ACCESSORY:-For secondary buds formed
besides a principal bud.
• RESTING:-For buds that form at the end of
growth season ,which will lie dormant untill
onset of the next growth season.
• DORMENT OR LATENT:- For buds whose
growth has been delayed for a rather long
time .The term is usable as synonym of
resting.
• PSEUDOTERMINAL:-For an axillary bud taking
over the function of terminal bud.

11. FOR MORPHOLOGY:-
• SALLY OR COVERED:-When scales,
also referred to as perule. Cover and
protect the embryonic parts;
• NAKED:-When not covered by scales.
• HAIRY:-when also protected by
hairs.

12. FOR FUNCTION:-
• VEGETATIVE:- If only containing
vegetative pieces: embryonic shoot
with leaves (a leaf bud is the same)
• REPRODUCTIVE:-If containing
embryonic flower.(a flower bud is
the same).
• MIXED:-If containing both
embryonic leaves and flowers.

13. FACTORS AFFECTING
DORMANCY
• Factors Affecting seed germination :
External and internal factor
• Some of the important factors are:
• External factors such as water, oxygen
and suitable temperature.2 internal
factors such as seed dormancy due to
internal conditions and its relesase.

14. EXTERNAI FACTORS:
• 1 WATER : A Dormant seed is generally
dehydrated and contains hardly 6-15% water
living cells. the active cells, however , require
about 75-95%of water for carrying out their
metabolism.
• Therefore the dormant seed must absorb
external water to become active and show
germination
• water also brings in the dissolved oxygen for
use by the growing embryo.

15. OXYGEN:- oxygen is necessary for
respiration which releases for respiration
which releases needed for growth
• Germinating seeds respire very actively
and need sufficient oxygen.
 SUITABLE TEMPERATURE: Though
germination can take place over a wide range
of temperatur(5-40c), the optimum for most
of the crop plants is around 25-30c.
• The germination in most cases stops at 0c and
45c.

16. • INTERNAL FACTORS
• Seed dormancy due to internal
conditions its release:
• In some plants the embryo is not fully
mature at the time of seed shedding
• Such seed do not germinate till the embryo
attains maturity.
• The freshly shed seed in certain plants may
not have sufficient amounts of growth
hormones required for the growth embryo.

17. • The seeds of almost all plants remain
viable or living for a specific period of
time.
• seeds of lotus have the maximum
viability period of 1000 year.
• Seeds germinate before the ending of
their viability periods.

18. REFERENS
• A Text book of college botany
- S. Sundara rajan

19. THANK YOU